A method and system for treating landfill leachate based on electrocatalytic oxidation

Abstract

A landfill leachate treatment method and system based on electrocatalytic oxidation is provided, wherein a nanofiltration membrane and a primary coagulation and sedimentation unit, a secondary coagulation and sedimentation unit, a primary electrocatalytic oxidation unit and a secondary electrocatalytic oxidation unit are provided, and the organic pollutants that are difficult to biodegrade are intercepted by the nanofiltration membrane, and the pollutants that are difficult to degrade are partially removed in the nanofiltration membrane concentrate by two-stage coagulation and sedimentation and electrocatalytic oxidation, and the biodegradability of the remaining organic matter is improved; most of the hardness is removed by adding a softener and intercepting a microfiltration membrane, and the hardness is further removed by resin exchange, and the organic pollutants in the concentrated brine are removed by electrocatalytic oxidation, so as to realize the full quantitative treatment of the biochemical effluent of the landfill leachate and the recycling of the salt, and avoid secondary pollution to the environment. The concentration of organic pollutants in the membrane concentrate is further reduced, and the accumulation of organic pollutants and salts formed by its reflux into the biochemical system is reduced, and the system process flow is simple and easy to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a method and system for treating garbage leachate based on electrocatalytic oxidation. Background Art

[0002] Landfill leachate is the liquid that seeps out of landfills due to stacking and landfilling, microbial fermentation, rainfall leaching, etc. It contains a large amount of refractory humic acid substances and a variety of highly water-soluble small-molecule refractory organic matter. It has high concentrations of pollutants such as ammonia nitrogen, total ammonia, COD, BOD, and a serious imbalance in the carbon-nitrogen (C / N) ratio. In addition, the inhibitory effect of high ammonia nitrogen on microorganisms further increases the difficulty of biological treatment. In 2008, my country promulgated GB 16889-2008 "Standards for Control of Pollutants in Municipal Waste Landfills", which puts forward higher requirements for the treatment of landfill leachate. In order to meet the emission standards, the "pretreatment + biological treatment + nanofiltration / reverse osmosis" process is widely used in the treatment of landfill leachate. Although the effluent quality of this process is good, the membrane system will produce 20% to 30% of membrane concentrate. The concentrate is enriched with a large amount of refractory organic matter, inorganic salts and trace heavy metals, and the composition is complex, which further increases the difficulty of treatment. At present, there is no effective treatment method for membrane concentrate, which makes it difficult to achieve full-scale treatment of landfill leachate.

[0003] In view of the above problems, a new technical method is urgently needed to solve the problems of substandard biochemical effluent quality in the traditional "pretreatment + biological treatment + nanofiltration / reverse osmosis" treatment process, the accumulation of pollutants caused by the reinjection of membrane concentrate, or the high operating costs introduced by the evaporation and crystallization technology. However, there are few studies on combining electrocatalytic oxidation with membrane treatment technology to treat biochemical effluent from landfill leachate, and there are no engineering application examples and few related literature reports. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method and system for treating landfill leachate based on electrocatalytic oxidation, which removes organic pollutants in the concentrated liquid through electrocatalytic oxidation, thereby meeting the water quality requirements of the evaporation crystallization device, realizing the full-scale treatment of the biochemical effluent of the landfill leachate and the recovery and utilization of salt, and avoiding secondary pollution to the environment; further reducing the concentration of organic pollutants in the membrane concentrated liquid, reducing the accumulation of organic pollutants and salts formed by its reflux into the biochemical system, and effectively reducing the membrane concentrated liquid that finally needs to enter the evaporation crystallization device, thereby reducing the operating cost. The system has a simple process flow and is easy to operate.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for treating landfill leachate based on electrocatalytic oxidation, characterized in that it comprises the following steps:

[0006] Step 1: subjecting the biochemical effluent of the landfill leachate to nanofiltration interception treatment, intercepting SS, COD, divalent ions, etc. in the wastewater into the nanofiltration membrane concentrate, and obtaining the nanofiltration membrane concentrate and the nanofiltration membrane produced water with monovalent salt as the main pollutant;

[0007] Step 2: After step 1, the nanofiltration membrane concentrated solution obtained is subjected to the following steps in sequence:

[0008] A1. Primary coagulation and sedimentation treatment, partially removes SS, heavy metals, calcium and magnesium hardness and COD in the concentrated liquid to obtain primary coagulation and sedimentation effluent; the generated sludge is transported to the sludge thickening tank through pipelines;

[0009] B1, subjecting the primary coagulation and precipitation effluent obtained in step A1 to primary electrocatalytic oxidation to partially remove COD in the water and obtain primary electrocatalytic oxidation effluent;

[0010] C1. The primary electrocatalytic oxidation effluent obtained in step B1 is subjected to secondary coagulation and sedimentation to further remove SS and COD in the water to obtain secondary coagulation and sedimentation effluent; the generated sludge is transported to a sludge thickening tank via a pipeline;

[0011] D1, subjecting the secondary coagulation precipitation effluent obtained in step C1 to secondary electrocatalytic oxidation to further remove COD in the water and decompose the macromolecular organic matter in the water into small molecular organic matter, thereby improving the biodegradability of organic pollutants;

[0012] E1. Returning the secondary electrocatalytic oxidation effluent obtained in step D1 to the biochemical system to further remove organic pollutants in the water, thereby achieving full quantitative treatment of organic pollutants;

[0013] At the same time, after step 1, the nanofiltration membrane produced water obtained is subjected to the following steps in sequence:

[0014] A2. Use a reverse osmosis membrane to perform reverse osmosis concentration and separation to obtain reverse osmosis produced water that meets the reuse water standard and reverse osmosis concentrated liquid containing high salt; the reverse osmosis produced water is reused, and the reverse osmosis concentrated liquid is subjected to the following steps;

[0015] B2. Softening the reverse osmosis concentrate obtained in step A2 to precipitate the alkalinity and calcium and magnesium ions in the concentrate to obtain softened effluent; the generated sludge is transported to a sludge thickening tank via a pipeline;

[0016] C2, subjecting the softened effluent obtained in step B2 to microfiltration interception treatment to separate suspended solids from water in the softened effluent, thereby removing alkalinity, calcium and magnesium ions, SS and part of COD to obtain microfiltration effluent;

[0017] D2, subjecting the microfiltration effluent obtained in step C2 to resin exchange treatment to further remove calcium and magnesium ions in the water, thereby obtaining softened effluent that meets the water inlet requirements of the electrocatalytic oxidation device;

[0018] E2, subjecting the softened effluent obtained in step D2 to electrocatalytic oxidation treatment to remove COD in the high-salt water to obtain pure concentrated brine that meets the water quality requirements of the evaporation crystallization device;

[0019] F2. Evaporation and crystallization of the pure concentrated brine obtained in step E2.

[0020] As a preferred solution, in step A1, flocculants and coagulants need to be added, and the supernatant enters the primary electrocatalytic oxidation unit.

[0021] As a preferred embodiment, in step B1, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0022] As a preferred solution, in step C1, flocculants and coagulants need to be added to the secondary coagulation and sedimentation, and the supernatant enters the secondary electrocatalytic oxidation unit.

[0023] As a preferred solution, in step C2, calcium carbonate and sodium hydroxide solution need to be added, and the supernatant enters the microfiltration membrane device.

[0024] As a preferred embodiment, in step D1, the current density of the electrocatalytic oxidation is 600-800 A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0025] As a preferred embodiment, in step E2, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0026] A landfill leachate treatment system based on electrocatalytic oxidation, characterized in that:

[0027] It includes a biochemical effluent delivery pipeline, and a biochemical effluent pool, a first delivery pump and a nanofiltration membrane which are sequentially arranged according to the flow direction of the biochemical effluent;

[0028] It also includes a concentrated liquid delivery pipeline, and a primary coagulation and sedimentation unit, a second delivery pump, a primary electrocatalytic oxidation unit, a secondary coagulation and sedimentation unit, a third delivery pump, a secondary electrocatalytic oxidation unit and a biochemical system arranged in sequence according to the flow direction of the concentrated liquid;

[0029] It also includes a water production delivery pipeline, and a fourth delivery pump, a reverse osmosis membrane, a softening device, a microfiltration membrane device, a resin exchange device, a fifth delivery pump, an electrocatalytic oxidation device and an evaporation crystallization device arranged in sequence according to the direction of the produced water flow;

[0030] It also includes a sludge thickening tank, a sludge conveying main pipeline and a sludge conveying pump arranged on the sludge conveying main pipeline, a first sludge branch pipeline from the first coagulation and sedimentation unit to the sludge thickening tank, a second sludge branch pipeline from the second coagulation and sedimentation unit to the sludge thickening tank, and a third sludge branch pipeline from the softening device to the sludge thickening tank.

[0031] As a preferred solution, the microfiltration membrane device adopts a tubular microfiltration membrane.

[0032] As a preferred solution, the pore size of the microfiltration membrane is 0.1-0.5 microns.

[0033] As a preferred solution, the resin exchange device uses chelating resin.

[0034] The beneficial effects of the present invention are as follows: the present invention proposes a method and system for treating landfill leachate based on electrocatalytic oxidation, which removes organic pollutants in the concentrated liquid through electrocatalytic oxidation, thereby meeting the water quality requirements of the evaporation crystallization device, realizing the full-scale treatment of the biochemical effluent of the landfill leachate and the recovery and utilization of salt, and avoiding secondary pollution to the environment; further reducing the concentration of organic pollutants in the membrane concentrated liquid, reducing the accumulation of organic pollutants and salts formed by its reflux into the biochemical system, and effectively reducing the membrane concentrated liquid that finally needs to enter the evaporation crystallization device, thereby reducing the operating cost. The system has a simple process flow and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The flowchart of one embodiment of the present invention is shown in FIG.

[0036] Figure 2 This is a diagram of the equipment layout of one embodiment of the present invention.

[0037] In the figure:

[0038] 1. Nanofiltration membrane; 2. Primary coagulation and sedimentation unit; 3. Primary electrocatalytic oxidation unit; 4. Secondary coagulation and sedimentation unit; 5. Secondary electrocatalytic oxidation unit; 6. Biochemical system; 7. Reverse osmosis membrane; 8. Softening device; 9. Microfiltration membrane device; 10. Resin exchange device; 11. Electrocatalytic oxidation device; 12. Evaporation crystallization device, 13 sludge thickening tank, 13A sludge main pipeline, 13A1 first sludge branch pipeline, 13A2 second sludge branch pipeline, 13A3 third sludge branch pipeline, 13B sludge delivery pump, 14.1 first delivery pump, 14.2 second delivery pump, 14.3 third delivery pump, 14.4 fourth delivery pump, 14.5 fifth delivery pump. DETAILED DESCRIPTION

[0039] Figure 1 The flowchart of one embodiment of the present invention is shown in the figure. In this example, a method for treating landfill leachate based on electrocatalytic oxidation is characterized by comprising the following steps:

[0040] Step 1: The biochemical effluent of the landfill leachate is subjected to nanofiltration interception treatment, and the SS, COD, divalent ions, etc. in the wastewater are intercepted into the nanofiltration membrane concentrate to obtain the nanofiltration membrane concentrate and the nanofiltration membrane produced water with monovalent salt as the main pollutant. In this step, the nanofiltration membrane 1 intercepts the SS, COD, divalent ions, etc. of the biochemical effluent into the nanofiltration membrane concentrate to obtain the nanofiltration membrane produced water with monovalent salt as the main pollutant.

[0041] Step 2: After step 1, the nanofiltration membrane concentrated solution obtained is subjected to the following steps in sequence:

[0042] A1. Coagulation and sedimentation treatment, partially remove SS, heavy metals, calcium and magnesium hardness and COD in the concentrated liquid to obtain primary coagulation and sedimentation effluent; the generated sludge is transported to the sludge concentration tank through pipelines;

[0043] B1, electrocatalytically oxidizing the primary coagulation and precipitation effluent obtained in step A1 to partially remove COD in the water and obtain primary electrocatalytic oxidation effluent;

[0044] C1. The primary electrocatalytic oxidation effluent obtained in step B1 is subjected to secondary coagulation and sedimentation to further remove SS and COD in the water to obtain secondary coagulation and sedimentation effluent; the generated sludge is transported to a sludge thickening tank via a pipeline;

[0045] D1, subjecting the secondary coagulation precipitation effluent obtained in step C1 to secondary electrocatalytic oxidation to further remove COD in the water and decompose the macromolecular organic matter in the water into small molecular organic matter, thereby improving the biodegradability of organic pollutants;

[0046] E1. Returning the secondary electrocatalytic oxidation effluent obtained in step D1 to the biochemical system to further remove organic pollutants in the water, thereby achieving full quantitative treatment of organic pollutants;

[0047] After the nanofiltration membrane concentrate enters the primary coagulation and sedimentation unit 2, the stirring equipment is turned on, and a certain amount of coagulant and coagulant aid is added through the dosing device for reaction. After the reaction is completed, the stirring is stopped, and the solid and liquid are separated after gravity precipitation. The supernatant enters the primary electrocatalytic oxidation unit 3, and the bottom sludge enters the sludge concentration tank through the sludge pump and pipeline. The primary coagulation and sedimentation can remove a large amount of SS, calcium and magnesium hardness, COD and various heavy metal ions. The primary electrocatalytic oxidation unit 3 further treats the primary coagulation and sedimentation effluent to remove part of the COD. The secondary coagulation and sedimentation unit 4 and the secondary electrocatalytic oxidation unit 5 can further remove the residual SS and COD in the water, and decompose the macromolecular organic matter in the water into small molecular organic matter, improve the biodegradability of organic pollutants, and then return the secondary electrocatalytic oxidation effluent to the biochemical system for further circulation and degradation.

[0048] At the same time, after step 1, the nanofiltration membrane produced water obtained is subjected to the following steps in sequence:

[0049] A2. Reverse osmosis concentration and separation to obtain reverse osmosis produced water that meets the reuse water standard and reverse osmosis concentrate containing high salt content;

[0050] B2. Softening the reverse osmosis concentrate obtained in step A2 to precipitate the alkalinity and calcium and magnesium ions in the concentrate to obtain softened effluent; the generated sludge is transported to a sludge thickening tank via a pipeline;

[0051] C2, subjecting the softened effluent obtained in step B2 to microfiltration interception treatment to separate suspended solids from water in the softened effluent, thereby removing alkalinity, calcium and magnesium ions, SS and part of COD to obtain microfiltration effluent;

[0052] D2: subjecting the microfiltration effluent obtained in step C2 to resin exchange treatment to further remove calcium and magnesium ions in the water, thereby obtaining softened effluent that meets the water inlet requirements of the electrocatalytic oxidation device;

[0053] E2 performs electrocatalytic oxidation treatment on the softened effluent obtained in step D2 to remove COD in the high-salt water and obtain pure concentrated brine that meets the water quality requirements of the evaporation crystallization device.

[0054] As a preferred solution, in step A1, flocculants and coagulants need to be added, and the supernatant enters the primary electrocatalytic oxidation unit.

[0055] As a preferred embodiment, in step B1, the current density of the electrocatalytic oxidation is 600-800A / m 2The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0056] As a preferred solution, in step C1, flocculants and coagulants need to be added to the secondary coagulation and sedimentation, and the supernatant enters the secondary electrocatalytic oxidation unit.

[0057] As a preferred solution, in step C2, calcium carbonate and sodium hydroxide solution need to be added, and the supernatant enters the microfiltration membrane device.

[0058] As a preferred embodiment, in step D1, the current density of the electrocatalytic oxidation is 600-800 A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0059] As a preferred embodiment, in step E2, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode plate and the cathode plate are made of graphene with a spacing of 2-10 cm.

[0060] Figure 2 The equipment layout diagram of an embodiment of the present invention is shown in the figure. In this example, a landfill leachate treatment system based on electrocatalytic oxidation is characterized in that:

[0061] It includes a biochemical effluent delivery pipeline, and a biochemical effluent pool, a first delivery pump and a nanofiltration membrane which are sequentially arranged according to the flow direction of the biochemical effluent;

[0062] It also includes a concentrated liquid delivery pipeline, and a primary coagulation and sedimentation unit, a second delivery pump, a primary electrocatalytic oxidation unit, a secondary coagulation and sedimentation unit, a third delivery pump, a secondary electrocatalytic oxidation unit and a biochemical system arranged in sequence according to the flow direction of the concentrated liquid;

[0063] It also includes a water production delivery pipeline, and a fourth delivery pump, a reverse osmosis membrane, a softening device, a microfiltration membrane device, a resin exchange device, a fifth delivery pump, an electrocatalytic oxidation device and an evaporation crystallization device arranged in sequence according to the direction of the produced water flow;

[0064] It also includes a sludge thickening tank, a sludge conveying main pipeline and a sludge conveying pump arranged on the sludge conveying main pipeline, a first sludge branch pipeline from the first coagulation and sedimentation unit to the sludge thickening tank, a second sludge branch pipeline from the second coagulation and sedimentation unit to the sludge thickening tank, and a third sludge branch pipeline from the softening device to the sludge thickening tank.

[0065] As a preferred solution, the microfiltration membrane device adopts a tubular microfiltration membrane.

[0066] As a preferred solution, the pore size of the microfiltration membrane is 0.1-0.5 microns.

[0067] As a preferred solution, the resin exchange device uses chelating resin.

[0068] The water produced by the nanofiltration membrane is reused after being treated by the reverse osmosis membrane. The concentrated liquid of the reverse osmosis membrane passes through the softening device 8, and sodium carbonate and sodium hydroxide solutions are added through the dosing device, and necessary coagulants and coagulants are added at the same time. After the stirring reaction by the stirring equipment, it is left to settle to achieve solid-liquid separation and remove the alkalinity, calcium and magnesium ions in the water. The bottom sludge of the softening device 8 enters the sludge concentration tank through the sludge pump and pipeline, and the supernatant then enters the microfiltration membrane device 9 and the resin exchange device 10 to further intercept and remove SS, calcium and magnesium hardness and part of COD in the water. The electrocatalytic oxidation device 11 further treats the resin exchange effluent to remove residual COD in the water, so that its effluent meets the water quality requirements of the evaporation crystallization device (evaporation crystallization device 12).

[0069] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for treating landfill leachate based on electrocatalytic oxidation, characterized in that: The following steps are involved: Step 1: subjecting the biochemical effluent of the landfill leachate to nanofiltration interception treatment, intercepting SS, COD, divalent ions, etc. in the wastewater into the nanofiltration membrane concentrate, and obtaining the nanofiltration membrane concentrate and the nanofiltration membrane produced water with monovalent salt as the main pollutant; Step 2: After step 1, the nanofiltration membrane concentrated solution obtained is subjected to the following steps in sequence: A1. Primary coagulation and sedimentation treatment, partially removes SS, heavy metals, calcium and magnesium hardness and COD in the concentrated liquid to obtain primary coagulation and sedimentation effluent; the generated sludge is transported to the sludge thickening tank through pipelines; B1, subjecting the primary coagulation and precipitation effluent obtained in step A1 to primary electrocatalytic oxidation to partially remove COD in the water and obtain primary electrocatalytic oxidation effluent; C1. The primary electrocatalytic oxidation effluent obtained in step B1 is subjected to secondary coagulation and sedimentation to further remove SS and COD in the water to obtain secondary coagulation and sedimentation effluent; the generated sludge is transported to a sludge thickening tank via a pipeline; D1, subjecting the secondary coagulation precipitation effluent obtained in step C1 to secondary electrocatalytic oxidation to further remove COD in the water and decompose the macromolecular organic matter in the water into small molecular organic matter, thereby improving the biodegradability of organic pollutants; E1. Returning the secondary electrocatalytic oxidation effluent obtained in step D1 to the biochemical system to further remove organic pollutants in the water, thereby achieving full quantitative treatment of organic pollutants; At the same time, after step 1, the nanofiltration membrane produced water obtained is subjected to the following steps in sequence: A2. Use reverse osmosis membrane to perform reverse osmosis concentration and separation to obtain reverse osmosis produced water that meets the reuse water standard and reverse osmosis concentrated liquid containing high salt; B2. Softening the reverse osmosis concentrate obtained in step A2 to precipitate the alkalinity and calcium and magnesium ions in the concentrate to obtain softened effluent; the generated sludge is transported to a sludge thickening tank via a pipeline; C2, subjecting the softened effluent obtained in step B2 to microfiltration interception treatment to separate suspended solids from water in the softened effluent, thereby removing alkalinity, calcium and magnesium ions, SS and part of COD to obtain microfiltration effluent; D2: subjecting the microfiltration effluent obtained in step C2 to resin exchange treatment to further remove calcium and magnesium ions in the water, thereby obtaining softened effluent that meets the water inlet requirements of the electrocatalytic oxidation device; E2: electrocatalytic oxidation treatment of the softened water obtained in step D2 to remove COD in the high-salt water to obtain pure concentrated brine that meets the water quality requirements of the evaporation crystallization device; F2. Evaporation and crystallization of the pure concentrated brine obtained in step E2.

2. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that: In step A1, flocculants and coagulants need to be added, and the supernatant enters the primary electrocatalytic oxidation unit.

3. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that In step B1, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode and cathode plates are made of graphene with a spacing of 2-10 cm.

4. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that: In step C1, flocculants and coagulants need to be added to the secondary coagulation and sedimentation, and the supernatant enters the secondary electrocatalytic oxidation unit.

5. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that: In step B2, calcium carbonate and sodium hydroxide solution need to be added, and the supernatant enters the microfiltration membrane device.

6. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that In step D1, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode and cathode plates are made of graphene with a spacing of 2-10 cm.

7. The method for treating landfill leachate based on electrocatalytic oxidation according to claim 1, characterized in that the steps In E2, the current density of the electrocatalytic oxidation is 600-800A / m 2 The action time is 20 minutes, the number of pairs of anode and cathode plates is 10-50 pairs, and both the anode and cathode plates are made of graphene with a spacing of 2-10 cm.

8. A landfill leachate treatment system based on electrocatalytic oxidation, characterized in that: It includes a biochemical effluent delivery pipeline, and a biochemical effluent pool, a first delivery pump and a nanofiltration membrane which are sequentially arranged according to the flow direction of the biochemical effluent; It also includes a concentrated liquid delivery pipeline, and a primary coagulation and sedimentation unit, a second delivery pump, a primary electrocatalytic oxidation unit, a secondary coagulation and sedimentation unit, a third delivery pump, a secondary electrocatalytic oxidation unit and a biochemical system arranged in sequence according to the flow direction of the concentrated liquid; It also includes a water production pipeline, and water produced by the nanofiltration membrane is delivered to the reverse osmosis membrane via a fourth delivery pump, and the treated water is reused, and a softening device, a microfiltration membrane device, a resin exchange device, a fifth delivery pump, an electrocatalytic oxidation device and an evaporation crystallization device are sequentially arranged according to the flow direction of the reverse osmosis membrane concentrate; It also includes a sludge thickening tank, a sludge conveying main pipeline and a sludge conveying pump arranged on the sludge conveying main pipeline, a first sludge branch pipeline from the first coagulation and sedimentation unit to the sludge thickening tank, a second sludge branch pipeline from the second coagulation and sedimentation unit to the sludge thickening tank, and a third sludge branch pipeline from the softening device to the sludge thickening tank.

9. The landfill leachate treatment system based on electrocatalytic oxidation according to claim 8, characterized in that: The microfiltration membrane device adopts a tubular microfiltration membrane.

10. The landfill leachate treatment system based on electrocatalytic oxidation according to claim 8, characterized in that: The pore size of the microfiltration membrane is 0.1-0.5 microns.

11. The landfill leachate treatment system based on electrocatalytic oxidation according to claim 8, characterized in that: The resin exchange device adopts chelating resin.

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